engine cuts out when driving, shows code P0251

Question

WHEN AT LIGHT THROTTLE SOMETIMES THE GLOWPLUG WARNING COMES ON THEN THE
ENGINE CUTS OUT WHEN DRIVING, SWITCH OFF THE IGNITION IT THEN RESTARTS WITH
LIGHT OUT AND THEN DRIVES NORMALLY AGAIN

Answer 1

P0251 is low pressure fuel pump output,the fuel pressure from the low side should be tested first then the high pressure side.